Unsurprisingly, cabin crew have a wealth of travel knowledge. Whether it's tips on how to avoid jet lag or the best snacks to take on a long-haul journey, flight attendants are the best people to go to for flight advice.
But they also have a number of methods that they keep confidential from passengers in order to communicate with each other, and help flights go smoothly. One, for example, is the secret reason they ask to see your boarding pass when you get onto the plane.
No, it's not for security reasons - and nor is it to help you find your seat. According to one cabin crew member on Quora, it's actually so they can assess the health and general wellbeing of the passenger, and make sure they're in a fit position to fly.
Myriam Mimi, a flight attendant for German airline Condor, explained the valid reason for asking for your boarding pass on the thread. "I check if they are drunk, drugged, sick, angry or afraid," she wrote. "That is extremely important as if I have the possibility to avoid any kind of troubles over the Atlantic, then I address it on ground. I say 'Hello, welcome on board', and I listen to how they respond."
Another flight attendant on the thread says they also use the meet and greet moment at the aircraft door to check whether a passenger is ill and may need further treatment on the ground. "I've had passengers board who look pasty and pale, deathly ill. We removed them; nobody wants their flu germs!" she adds.
So next time you find yourself flustering for your boarding pass at the plane door, know that it's for a decent reason - and hopefully means you won't end up sitting by someone with the flu.